Does the Alternating Series Converge Conditionally?

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SUMMARY

The discussion centers on the convergence of the alternating series defined by the equation An = n/(1 + nLNn). It is established that this series converges conditionally, as it meets the necessary criteria: the limit of the last term approaches zero and the terms are non-increasing. The derivative d/dn An = (1-n)/(1+nLNn)^2 is used to verify the non-increasing condition. Participants are encouraged to utilize L'Hôpital's rule for further analysis.

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Homework Statement



heres the equation that will converge conditionally: http://img440.imageshack.us/img440/9945/untitled3jg.jpg

changes to
An = n/(1 + nLNn)

Homework Equations


alternating series equation.
converges conditionally.

d/dn An = (1-n)/(1+nLNn)^2

The Attempt at a Solution



I'm not sure how the first equation changes to the second equation, and then I'm supposed to use l'hospital's rule.

any help please.
 
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Is the equation in the picture meant to read [tex]\sum_{n=2}^{\infty}\frac{(-1)^nn}{1+nlNn}[/tex]?

Try to learn LaTex; it's very easy to use. Click on the equation to see the code. The tutorial is here: https://www.physicsforums.com/showthread.php?t=8997
 
An alternating series converges if it meets two conditions: The last term converges to zero and the terms, ignoring the signs, are non-increasing.

The 1st one is met easily. for the 2nd check check the derivative, if its negative for positive infinity, then it converges.
 

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